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Is there a get around to make $\surd$ variable-sized via standard AMS package? For example, I would like $\surd \frac{a}{b}$ to look like $\sqrt{\frac{a}{b}}$ with the elongated left line but no overline on $\frac{a}{b}$.

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Welcome to TeX.SX! – Christian Hupfer Aug 7 '14 at 6:15
Hi! It's a nice question. However, from the perspective of math typography, such usage of this symbol is discouraged. It's preferable to always typeset the horizontal bar over the expression you make a root of: \[ \sqrt{\frac{a}{b}} \]. Another solutions for your example are: \[ \frac{\sqrt{a}}{\sqrt{b}} \] (that's what I prefer) or \[ \Bigl(\frac{a}{b}\Bigr)^{1/2} \]. – yo' Aug 7 '14 at 6:52
@tohecz Thank you for your reply. While I prefer the same style '$\sqrt{\frac{a}{b}}$' that you have suggested, my department is trying to adopt '$\surd$', which seems to be the standard notation for square root employed in Cambridge A-Level examinations. Thus, I am looking for ways to make the symbol '$\surd$' to match '$\sqrt$', minus the overline. – user60342 Aug 7 '14 at 8:19

Use the following definition:


and the test:

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You probably want to have also the option of setting the root index; with xparse it's rather easy:






enter image description here

Of course, seeing the result I ask myself why a respected institution wants to change a long time honored notation.

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This is the root of ugliness :-/ Especially the LHS. – yo' Aug 7 '14 at 8:54

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